search for: defslot

...ead at instruction which sets it (i.e. not used later) > // the live interval ends at the next instruction Actually it ends at the same instruction. Each instruction has 4 slots. So instruction 0 spans interval indexes 0-3, instruction 1 4-7 and so on. In the case above the interval added is: [defSlot(instr), defSlot(instr)+1) You may notice that this interval is "empty" in the interval indexes discrete world (i.e. [13,14)). Indeed it is, and its only purpose is to naturally express this clobbering of physical registers to the register allocator. For example given [13,14) for some phy...

I've just spend some time looking at the above function, and while I understood what it does, a comment would have helped a lot. Maybe, something like: // Determine the end of the live interval for this register // For physical register, all internvals are within basic blocks so // we look for the instruction in this basic block which last uses it. The first loop might have a comment like: